Method for cleaning, clearing, and/or treating an elongate path

ABSTRACT

The invention relates to a method for cleaning, clearing, and/or treating an elongate, particularly rectilinear paved path, especially a taxiway and/or take-off runway and/or landing runway of an airfield, said path being used in the longitudinal direction in successive, irregular intervals by starting or landing aircraft. In said method, cleaning or clearing movements in at least one segment of the path are carried out in cycles, at a defined operational width and at an oblique or right angle relative to the longitudinal direction of the path, by two or more identical, successive cleaning or clearing runs and/or movements of at least one clearing apparatus.

This invention relates to a procedure or method for cleaning, clearing and/or treating an elongate path, especially a straightly paved runway, especially the runway and/or the airstrip of an airfield with the features of the independent claim 1.

Airstrips and areas being in use throughout the whole year have to be cleaned and/or de-iced depending on their type of use. This concerns runways and airstrips of airports for example. Owing to their considerable length, these so called runways will entirely be closed for the air traffic before being freed from snow, snow slush, ice, packed snow or as the case may be. Shortly before the decision to close the runway completely the air traffic may only be maintained in places while accepting losses regarding the security. The steering and breaking behaviour of starting and landing aircrafts is considerably deteriorated on airstrips which are not completely cleared from snow. In case of sudden snowfall the deterioration of these conditions may happen within shortest time and hence very surprisingly.

In road traffic a clearing of the streets is possible during moving traffic without any problems. Due to the considerable speed differences of snow-snow-clearing vehicles and aircrafts, a clearing during take-off and landing is definitely not possible. For this reason, all areas have to be completely closed off for a clearing of the runways for the air traffic. Depending on the length of time which is required for a complete clearing, several take-offs and landings will be impossible.

Schematic representation of FIG. 1 shows a conventional clearing procedure of a so called runway 10 of an airport. The clear-up runs of a snow plough convoy 12 will exclusively be done in direction of travel 14 to right the hand-side. Waiting aircrafts have to circle during the relatively long period of clearing. Not until the completion of the clearing has been finished, they can begin the final descent 20. During the clearing period the runway 10 is closed for landing and taking-off aircrafts. Circling aircrafts 16 have to bridge the period with additional fuel reserves. The effective clearing period results from as follows: the time the snow-clearing vehicles which are mostly ordered in series need to drive onto the runway. The time the snow-clearing vehicles need to order themselves in series or next to each other. The time needed for clearing a runway 10 which has a length of several kilometres. The time which is needed to reorder the snow-clearing convoy 12 at the end of the clearing process so that the vehicles are standing in a row again. In so doing, the snow-clearing vehicles can leave again the runway 10 via a taxiway.

Under the supposition that the clearing period of 60 m wide and 4 km long runway approximately takes 20 minutes, whereas the snowfall intensity is increasing in such a way that within 19 minutes a sufficient breaking action is no longer guaranteed, the runway has to be cleared once again. Virtually, no single landing would be possible after the first or before the second clearing process. Furthermore, it is supposed that a second clearing convoy would be available 19 minutes after the first clearing convoy being in use at the beginning of runway 10 in order to clear the runway 10 from snow which has been fallen in the meantime. In this case, the runway 10 would have been closed for 40 minutes. Such a situation may occur at the runways of any airport. The airport will have to be closed in case of considerable snowfall as above described. Furthermore, the great number of clearing convoys will also lead to the closure of the airport. In case of heavy snowfall over a long period which may be the case in North-American areas where blizzards are quite common it may also be possible that potential alternate airports have to be closed suddenly.

A procedure for removing ice and/or pressed snow layers covering circulation areas is known from AT 413564 B. In so doing, ice and snow layers will be cut by means of circular saw blades. Furthermore, water will be injected in order to simplify the ice layer being removed from the ground.

One objection of the present invention lies in the fact that the circulation areas and straightly paved runways will be cleared within shortest time. Simultaneously, the main purpose of the runway will be affected as few as possible.

This procedure is solved with the characteristics of the independent claim 1 by cleaning and/or clearing the runway in any angle or vertical to its longitudinal direction. Characteristics regarding favourably continued construction are found in dependent claims.

According to the present invention, the clearing of the runway is made by carrying out the clearing movement of at least one sector of the runway with a defined working width in an oblique or vertical angle to the longitudinal direction of the runway and in cycles of two or more equal, successive clearing and cleaning routes of at least one clearing device. This concerns a runway which is frequented by vehicles, taking-off or landing aircrafts in longitudinal direction in successive, irregular periods.

Whereas in conventional procedure, the runway is cleared between the narrow and front sides the inventive procedure describes a clearing movement between the opposite long sides and flanks of the runway. A clearing movement can be a clearing route, whereas the whole device is moving correspondingly.

This inventive procedure preferentially enables the clearing process to be done by several and parallel clearing movements which are laterally displaced by the working width to the longitudinal direction of the runway.

Optionally, a clearing movement may be followed by a return in opposite direction without clearing or cleaning and thereto a laterally displaced clearing and/or cleaning movement in the same direction to the previous clearing movement. Alternatively, a clearing movement in one direction may be followed by a laterally displaced clearing movement in opposite direction and thereto a laterally displaced clearing movement in the same direction to the previous clearing movement. According to conditions or requirements, these alternatives may be combined or varied in any way.

The advantages of the inventive procedure will especially take effect if two or more clearing movements are done simultaneously or time-displaced in different areas along the longitudinal direction of the runway. Hence, several vehicles or clearing devices will be able to clear the runway simultaneously in different areas. This leads to the fact that the required time will be reduced considerably. The more areas of the runway will be cleared simultaneously, the shorter is the overall time required for the clearing of the whole runway or parts of it. The conventional procedure describes a clearing in longitudinal direction with one, two or more vehicles taking less than 10 minutes for clearing in case of a typical airstrip of 2 km or more and a limited speed. If required, the inventive procedure enables the airstrip to be cleared much faster.

A further alternative is to clear the runway by means of at least one snow-clearing vehicle, especially by means of two, three or more snow-clearing vehicles running simultaneously and/or time-displaced. Considerable advantages may occur when clearing the runway with one vehicle compared to the clearing of the runway in longitudinal direction. That is because mostly required areas can be cleared preferentially. For the first time, it is possible to clear the runway within shortest during its uninterrupted use in case of two, three or more parallel used vehicles clearing the runway optionally synchronically or in any way in different areas—either in zig-zag or repeat mode with empty return runs.

For this reason, an especially favourable option of the inventive procedure is to drive along the runway with at least one clearing and/or cleaning vehicle while the runway is used in longitudinal direction by other vehicles or aircrafts. As soon as the runway is used in longitudinal direction as it is its principal purpose—e.g. usage by starting and taking-off aircrafts—it is sensible for safety reasons to put the at least one snow-clearing vehicle laterally on the roadside or spaced to the roadside. During the runway being in use, the snow-clearing vehicle can in longitudinal direction remain in standby position. The snow-clearing vehicles can go on clearing and cleaning immediately after the vehicles or aircrafts passing by and after leaving the runway.

In so doing, the runway can be cleared and cleaned until shortly before being used in longitudinal direction and/or directly after being used in longitudinal direction or in vertical angle to the longitudinal direction. Consequently, cleaning and clearing only has to be interrupted for a short time and after the passing of the aircrafts or vehicles the clearing process may be continued again.

An especially time-serving option of the inventive procedure is that sections of the runway, having been passed already, can be cleared and/or cleaned by one or several snow-clearing vehicles while further sections are being used in longitudinal direction by aircrafts and vehicles. For this option of the procedure it is not absolutely necessary to clear the runway completely in order to clear and clean it in lateral direction. It may also be sufficient to clear and clean the runway again behind the aircraft, however in a sufficient safety clearance. In front of the vehicle or aircraft passing the runway in longitudinal direction a larger safety clearance should be included in movement direction in order to prevent every potential collision.

Furthermore, it may be advantageous to steer the clearing and cleaning vehicles in defined lanes and/or observe their movements permanently. This will be realized by means of optic, inductive, radio based and/or satellite based lane keeping steering systems or with the aid of such systems (like GPS/Glonas/Galileo-System). In so doing, an automated or semi-automated clearing procedure can be made possible. Control or remote control of the vehicles may also be executed or facilitated by means of induction loops, radar, wireless, railing systems.

When talking of clearing and cleaning routes in the present connection this basically means all kinds of clearing and cleaning movements of all kinds of cleaning and clearing devices and/or vehicles. This does not necessarily involved vehicles of conventional construction. Clearing and cleaning movements may equally be executed by means of cable controlled devices.

Listed below, several aspects of the present invention will be summarized again. This invention concerns a procedure favouring the removal of snow, slush, ice, dirt, alien elements, rubber, water or as the case may be. Briefly speaking, contamination on straightly paved runways, especially on airstrips. When talking of runways in the present connection, this means the expanse of airfields, airports or aircraft carriers used by taking-off aircrafts for acceleration in order to reach the necessary speed for take-off. In most cases, the airstrip is also the landing strip used by aircrafts for landing and breaking. As runways and landing strips are used for both purposes they are simply called airstrips. Pilots and flight controllers simply call it runway which is common in English language. The direction of the runway is the direction in which the aircrafts are landing and taking-off.

The runway will not be cleared, cleaned or treated with certain agents (de-icing fluids, salts, thawing salts, sands etc.) analogically in longitudinal direction to the runway direction while the air traffic is closed. It will be cleared in an angle deviating from the conventional clearing direction.

In an extreme case, cleaning, clearing and disperse devices go or cross the runway across the airstrip. In so doing, contamination is removed from the runway. In addition to that, certain agents will be used. Compared to a cleaning movement in longitudinal direction (prior art) which may reach a length of more than 4 km and may last up to 30 min a clearing movement in lateral direction takes only few seconds for approximately 60 metres. Hence, it is possible, to clear the runway while aircrafts are landing and taking-off. Moreover, it is possible to clear the runway in sequences after the landing or taking-off aircrafts passed the respective sequence. By means of the new procedure, existing safety distances between aircrafts for separation, wakes etc, which are converted, measured and expressed in periods will be used parallel. The runway has no longer to be closed for the air traffic. In other words, a staggering distance of two minutes for example (laid down in law) is used parallel during air traffic between two successive aircrafts which use the runway for taking-off or landing. In so doing, the runway can at least be cleared and treated sequentially. The proof of operationality offers vehicles e.g. waiting in front of runways which are in operation on airports with several maybe parallel running runways in order to cross the runway after the passing of a taking-off or landing aircraft. This may involve a just landed aircrafts crossing a further runway with a normal speed of 5 to 15 nodes in order to reach the passenger terminal. Coordination will be made by flight controllers. Air traffic will not be impaired by crossing an active runway in such a way.

The present invention may simplified be referred to as so called crosswise movement. Especially agricultural vehicles are suitable for the realisation of this procedure. Until now, vehicles similar to trucks and equipped with tools have been used for clearing the snow. These vehicles are basically used for cleaning streets and runways. Special-purpose machines, however, are more suitable for the present purpose. These vehicles will particularly advantageously be used for the special purpose of clearing the airstrip.

Such a vehicle may advantageously have a driving motor as being used for traction engines and tractors in agriculture. A so called power shift gearbox without interrupting the traction when changing the gear should be used in stead of a conventional manual transmission interrupting the flux from the motor to the transmission. A so called power shift gearbox should be used for gear shifting instead of a conventional manual transmission interrupting the flux from motor to transmission during the switching operation. Preferably, an infinitely variable transmission is used. By means of this, the driver can sensitively adapt the speed to the requirements without interrupting the traction.

Conventional snow-clearing vehicles have tyres also used for trucks. These tyres inflated with air pressures of several bar are absorbing the load and transmitting the drive. These tyres are suitable for the usage on paved runways, streets etc. without destroying them.

A considerable damage to the agricultural area is caused by deviating from the runway e.g. into the green area next to the airstrip. These tyres are normally not suitable for off-road use. The tyres of the currently used vehicle should provide a well cross country mobility. This vehicle can be carried, transported and powered by low pressure tyres causing a much lower ground pressure over the prior art (for runway equipment). The ground pressure may be reduced by increasing the width and contact area (of belt drive systems etc.) and by twin tyres, increasing the number of axes. This has been developed in countless versions for the agricultural sector. If applicable, the diameter of the tyres may be so large that it is possible to cross larger snow piles at any time. Furthermore, treads may be developed in such a way that the traction on snow, grasslands and paved grounds is ensured at any time. The steering or remote steering of vehicles may be carried out or supported by means of GPS or GPRS. Furthermore, working widths of more than 3 or 6 metres may be available. In contrast to state of the art road sweepers and snow-clearing vehicles, the available working width will be considerably increased. Furthermore, it may be advantageous to use lightweight construction for the snow-clearing vehicle, to reduce the operating speed of 30-50 km/h (for snow-clearing vehicles on so called S- or L-runways) dramatically, to develop the tools smaller sized (e.g. height or diameter) and lighter in relation to the state of the art.

Instead of automotive vehicles the movements of the machines may optionally be executed by means of self propelling, tow ropes, chain tracks, poles (push and pull) or traction machines or pushers. In order to prevent vehicles from driving into the security zone (during landing or take-off) so called chains e.g. electronically controlled or (visual) barriers can prevent uncoordinated movements.

According to suitable constructional measures obstacles along the runway can be crossed over by means of corresponding excavation i.e. the vehicle will be lifted, the tyres will avoid the obstacles.

In order to be able to monitor the no-slip conditions of the runway at any time, it may be reasonable to determine the measured frictional coefficient or the calculated breaking coefficient not only over a narrow track but also over a large expanse of the runway (up to the complete expanse of the runway). Determination will be made by means of force measurement, bolt measuring and/or saving resistance of a vehicle unit, absorption of energy of tools, braking action. Furthermore, these data will be transferred if applicable in real time to the operational command.

Furthermore, it may be advantageous in connection to this particular procedure not to spread the de-icing fluid or other agents over large areas but selectively on certain surface areas covered with packed snow.

In connection to the above mentioned procedure, a multiple application by means of the same or corresponding equipment is possible, also synchronically or simultaneously. In detail this includes winter road clearance (clearing, spreading of de-icing agents, adhesive agents etc.), removal of sudden ice, clearing of transverse grooves, removal of rain water, general clearing of S/L runways, dust, dirt, foreign objects, animals, etc, measurement of braking coefficient (partly or all over) driving or keeping away animals in the area surrounding S/L runways or air traffic etc. a removal of rubber abrasion (of aircraft tyres).

Furthermore, contamination will laterally be moved to the clearing direction and if applicable, directly loaded or spread on unpaved areas by means of nearly flat lying conveyors (or the like) on which contamination of any kind is moved on.

Contamination may be moved and/or gathered in containers, conveyors and if applicable, loaded or unloaded on impassable areas or in containers.

Furthermore, measures can be met to reduce fog or to improve runway visual rage values at least for a short time during emergencies. In addition to that, inspection and/or control passes can be made with an anti-snow drift mode.

The power unit (motor drive) may be separated from the tool unit in short order. Hence, depending on the fault, the tool or the engine may be exchanged fast and easily. Moreover, during the summer months, the tools showing wear parts can be overhauled and the power unit can be used for different application fields and the profitability can be improved considerably throughout the year. In addition to that, by means of light coupling of tools for the winter S/L treatment with a power unit, the power units can be linked, leased or rent.

An increased effectiveness of snow and ice removal may be achieved by

-   -   increasing the number of clearances,     -   increasing the number of flight movements,     -   optimizing the use of de-icing agents specifically (in relation         to time and surface),     -   preheating de-icing agents (maybe with the lost heat of power         units),

Further modifications and alternatives of the inventive procedure, if applicable by the use of one machine variant described before and/or under consideration of one or more boundary conditions mentioned before are possible and reasonably and thus part of the present invention. In this context, it should be pointed out that the inventive procedure refers to all possible crossings on elongated runways e.g. for driving away birds and different applications as described above.

The power distribution of the used devices, which is necessary for the treatment of the runway, is done mechanically (e.g. waves, chains, ropes, belts, straps, frames etc.), hydrostatically or electrically over the whole working width. Entire working width can be carried out by means of several parallel or side by side placed and linked modules. In addition to that, the modules can be swivel-mounted.

A remote control of all devices can be carried out by means of different procedures as e.g. Bluetooth, GPRS; radio, GMS, satellite communication, isobus, infrared, radar and so on. In contrast to the so called procedure in longitudinal direction a crossing in transverse direction would be similar to an evacuation. A procedure in transverse direction can be interrupted in few seconds. In contrast to that, a procedure in longitudinal direction can lead to considerable delay due to longer distances.

An especially advantageous alternative is the simultaneous measurement of the braking coefficients during clearing in order to be able to vary the speed in dependence upon the braking process by means of the feedback so that a clean runway is possible after the treatment. In case of strong snow fall, a lower braking coefficient will be ascertained by which the speed will be reduced. In so doing, a better clearing quality and a higher security will be guaranteed.

In the following, the invention will be explained in detail by means of variants referring to the enclosed drawings. The variants serve as example and may not be seen non-restrictively. Same parts and elements in the figures are basically characterized with the same digit. For this reason, some of these digits will partly not be explained repeatedly.

FIG. 1 shows a conventional clearing procedure according to state of the art.

In schematic representations FIGS. 2 to 10 show variants of an inventive clearing procedure.

In FIGS. 11 to 17 the conventional procedure in longitudinal direction is compared with the inventive procedure in lateral direction and the integratability in the running air traffic.

The situations which should be improved by means of the inventive procedure are best-described on the basis of an experiential report of a pilot. The state of affairs caused as a result of the insufficient, presently available clearing procedure is described in the following report:

“On XX.YY.ZZZZ we took-off with a long-haul jet from Tokyo towards B. The weather forecast predicted snowfall for the estimated time of arrival. Considering the restriction regarding the take-off weight we were not allowed to add extra fuel in case of holding patterns over B. The maximum of fuel was barely sufficient for flying holding patterns of less than one hour”. (Note: When flying a holding pattern lasting one hour at the destination approximately 6 tons fuel plus fuel for a 12 hours flight for transporting the extra fuel were calculated. In so doing, the entire additional fuel amount of nearly 10 tons is necessary as a result of the expecting snow conditions. For this reason, freight of similar weight had to be left behind in Tokyo.)

The experience showed that in case of comparable weather forecasts, additional fuel in above mentioned amount was filled in. However, the weather situation on the destination airport did not correspond to the forecast and the situation was entirely without tense. This time, however, we also had to bear the worst case in mind. After arrival in the country of destination, still far away from B, we had to stop in a holding pattern for approx. 40 minutes according to the order of the air traffic controllers. This led to a considerable delay of our flight. After flying further towards B we had to stop in a further public holding pattern. During this time, we contacted our station in B and transferred our position in space and in the approach sequence between the other aircrafts waiting in the sky. Thereby, we are talking of larger aircrafts as smaller air planes with short flight time did not get permission for take-off. These air planes were sensibly waiting on the ground for the improvement of the situation. The company station arranged to change the approach order with a different aircraft having enough fuel on board and belonging to our airline. This measure was met even if the scheduling of air controllers, airport, company, crew, air craft rotation, connecting flights etc was confused. In so doing, we were briefly number 2 and we were able to start the approach as no. 2. The additional fuel intended for waiting was nearly completely consumed. As we were no. 1 the allocated runway was completely closed for approx. 20 minutes because the snowplough was in use to clear the runway. Before, the aerogram of pilot who just landed reached the tower describing the braking action as poor. A direct measurement with the friction meter auto did not take place. The parallel runway in B has been closed since this morning, because of an aircraft which slided-off the runway as a result of the snow. Recovery operations may last some more days. On the one hand, there were no landing opportunity in B and on the other hand we were out of fuel. The landing at an alternate airport C with the same weather conditions was initiated. Fortunately, the approach was without delay. Contrary to expectations, the runway was completely free of ice and snow. The braking coefficient was excellent as to be expected on a merely wet runway. This solely resulted from the fact that air traffic was low and due to the accompanied use of the considerably shorter runway as a result of snowplough. The snow fall was nearly the same. It was out of question for almost all guests having connecting flights in the same evening to reach their final destination. They had to be prepared for an irregular stay in Munich. Consequently, we managed guests with the destination C to get off. However, we had to carry on their luggage to destination B where we were able to unload the container at the earliest. According to the procedure, a forwarding of the luggage should be planned the following day. As a result of the snow chaos however, this has not been possible.

A further item on the priority list was to organize 20 tons of jet fuel/kerosene, to de-ice the long-haul jet completely my means of a basically small de-icing vehicle for short-haul jets. There are only two de-icing vehicles. However, being already in action in C. As a result of snowfall which has been quite heavy in the meantime, the hold-over time (timeframe after de-icing in which a secure take-off is possible) has always been lower. So the total of all periods between the beginning of the anti-icing of the first section of the airfoil wings and the completion of the de-icing or plus rolling period to the runway plus possible delays as a result of slot guidelines/targets, landing, taking-off and clearing probably led to the fact to stop in C. Repeating the anti-icing procedure after passing the hold over time would lead to the expiry of the maximum operational hour which is 20 hours. Furthermore, the technical procedure for the flight back to B must have been organized. Moreover, the situation in B must have been observed and the maximal working hour of the crew had to be calculated after 16 working hours. All this had to be coordinated with the new time of arrival which was calculated in a new flight plan. The captain was able to prolong the working hour. Fortunately, the crew did not get off in C which would have consequences for guests, freight, aircraft, successive plans, alternative crew etc. Keeping in mind the devastating aircraft catastrophe in Tenerife, we exercised care despite approaching fatigue in the late evening. At that time, much more aircrafts had to go to the alternate airport to Tenerife which contributed to the disaster already. Approaching the nightly B, a CAT-3 approach followed as a result of viewing conditions because of heavy snow fall. Due to the necessary staggering, the CAT-3 approach took much longer. In contrast to a cleared merely wet runway in C the runway in B was contaminated with several centimetres of snow. In the second half of the runway it confirmed that the rear part has not been cleared (probably lack of time; luckily, the wind hold to the facts of the runway conditions and did not turn. In so doing, along the delay for changing the direction of the runway considerable delays due to clearing the consequently first section of the runway would occur. At last, the exceeding of the working hours must have been reported to the Luftfahrtbundesamt (German federal aviation administration). Finally landed in B, we missed the turn-off taxiway intended for us as the delay rate has not been sufficient and a secure speed corresponding to the snow-covered runway has not yet been reached.

After passing the free turn-off taxiway we would indeed have been slowly enough, however, the air controller directed us to the end of the road because there was no open, free or cleared runway in between. Our estimated final distance was 1.5 km, the speed of our aircraft including 14 crew members, more than 250 passengers and 20 tons of fuel (approx. 180 tons total weight) was 15-20 km/h. This meant further 5-6 minutes on the only runway in Y. We heard over the radio that a following aircraft had to take-off due to our delay/stay and we received the instruction “expedite vacation”. We have been accelerating in order to reach our final position fast and we have been rolling over the snow-covered runway. After nearly 18 working hours and at the end of the runway, we were surprised. Different to the first section of the runway covered compacted snow and a more or less existing braking coefficient (similar to chemically de-iced wet runways) was nearly zero shortly before the end of the runways and taxiways. Neither brake nor steering seemed to work, the speed was suddenly too high. Immediately, you think on crosswise groofings on the surface. Once you need them, they were filled with snow, moreover, the cover of snow will possibly be stabilized thereby and less or even no deceleration will be guaranteed. Only the quick-thinking reverse thrust of the captain could prevent an uncontrolled leaving of the remaining runway. Contrary to the regulations to make a maximal reverse thrust with a speed of only 70 nodes (more than 130 km/h) we decided not to do so and the aircraft came to standstill. As a result of overheating the engines could be damaged or foreign substances could get into them. The engines were secondary. In addition to that, so much snow was whirled up the reserve thrust that you hardly could see the ground. Again a compromise had to be met within a fraction of a second. Due to snowfall and almost two accidents the airport B would have come to standstill for a longer period.

Alone the fact that a flight as described above could become reality is sufficient. The above mentioned example should describe the state of the art difficulty from the viewpoint of persons concerned. Considering the snow masses for example, you will find out that these snow masses will not be pushed away from the runway on the shortest way. However, they will be pushed away in a vector orientated to the edge of the runway but leading over the runway over a longer distance. In other words, tonnages of snow will not be pushed directly at right angle to the direction of the runway but over a longer distance in direction of the runway in order to leave the runway after several 100 metres. This requires time and power of impact.

An improvement of the current state with its history in terms of a complete elimination of the problem seems hopeless without the present invention. Despite sophisticated aircraft de-icing procedure the air-traffic is helpless in face of the whether and in face of many individual aspects.

For example, the development of automotive de-icing elephants and many other devices could solve big problems. However, snow-covered and contaminated runways have become a main problem. See above. Even if the chemistry seems to solve the problem it only shifts it as you can see in the example of the delivery bottleneck of the raw material de-icing liquid at the beginning of the year 2006 and the air traffic and the air-traffic came partly to standstill again. The daily loss as a result of an onset of winter can amount to millions. However, contaminations like dust and tyre abrasion which is quite common during the summer months and during long dry periods, or lost component parts of aircrafts etc. can cause serious consequences. The air crash of a Condorde in Paris and possibly even the withdrawal of the Concorde from the air traffic as well as countless different incidents and damages would have been prevented if the runway had at least sequentially been cleared during the day permanently and prophylactically.

However, foreign materials like birds, flock of birds and other animals are found directly over, next to and on the runway or even in the air. These animals startled by approaching aircrafts always find their way into the sensitive engines and into the baromatic measuring instruments. Consequences and damages are enormous.

The present invention is solving the described problems and improving the actual state regarding contaminated runways etc. in this way, that difficulties and disturbances will be a thing of the past for pilots, airlines and airport operators. The currently weakest link in the chain (e.g. the insecure runway conditions in winter) could become in foreseeable future the strongest link in the chain—runways which are ensured to be open, ready to operate on and clear.

The schematic representation of FIG. 2 example shows how to realize the inventive procedure. On runway 10 there is a snow-clearing vehicle in form of two vehicles behind a safety line 24. Furthermore, behind this safety line, an aircraft 26 is waiting on the ground to cross the active runway 10. The snow-clearing vehicle(s) 22 waiting to go into action receive—alike the waiting aircraft 26 on the ground—the opening for crossing the runway 10 directly or indirectly from the tower (air controllers) after a landing aircraft 28 passed by. An upper safety line 24 which is parallel to the lower safety line 30 preferentially has the same distance to runway 10 and is like the upper safety line 24 parallel to runway 10. The safety lines 24 and 30 define the distance between the snow-clearing vehicles 22 and the runway 10 as well as the distance between waiting aircrafts 26 and the runway as long as active i.e. landing or taking-off aircrafts 28 are able to pass the runway 10.

In the situation described above, the following announcement may occur via radio: “aircraft 26 and snow removal group, after landing traffic on short final cross runway 10.” Similar to the rolling aircraft 26, the snow removal group SRG will be confirming and responding as follows: “snow removal group, after landing traffic on short final, cross runway 10.” Hence, all users listening to the same frequency will be informed. Suitable announcements may secure that snow-clearing vehicles will not cross the runway until the runway has been opened by means of explicit announcements.

The representation of FIG. 3 shows the following situation: aircraft 28 has been landed and passed the snow-clearing vehicles 22 and the waiting aircraft 26. As soon as above mentioned situation occurs, vehicles 22 and aircraft 26 get in motion and cross runway 10. For crossing the runway 10 the snow-clearing vehicles 22 use their tools like snow clearing blades, ice scrapers, road sweepers, devices for shredding ice, dew or de-icing fluid spraying devices and/or dispersion devices for sand or salt.

A further schematic representation of FIG. 4 shows a situation after snow-clearing vehicles 22 crossing runway 10. After the snow-clearing vehicles 22 having operated on runway 10, the vehicles move away from the runway to behind the safety line 30 (right) similar to the rolling aircraft or the landed aircraft, this happens during the tools being in use. Depending on the working width and the number of snow-clearing vehicles 22 or snow removal groups the entire runway could have been cleared already. However, this example shows how to proceed with only few snow-clearing vehicles 22. Thus, the first section of the runway 10 is cleared and possibly treated with de-icing agent. A further aircraft is approaching the runway 10, further landing aircrafts (not shown) are following in short distance.

A further schematic representation shows the snow-clearing vehicle 22 or the snow removal group(s) 22 positioning themselves again behind the right safety line 30 in order to cross the runway 10 once again. The aircrafts 22 are waiting for the landing aircraft 32 passing by. The only result of this may be that the vehicles have to execute a transposition manoeuvre or a transposition manoeuvre with a displacement of distance corresponding to the length of a runway section being cleared in one operation process (refer to FIG. 7) depending on the angle removing from (FIG. 6, angle α) or approaching (FIG. 6 angle β) the runway 10. Depending on the available working width, the necessary parallel space behind the safety line 30 may vary.

The procedure corresponding to FIGS. 2 and 5 can start from the beginning with the only difference that the following runway section is being cleared.

The schematic representation in FIG. 7 a shows a variant with 3 snow removal groups 22 in total so that the runway can be cleared and treated completely after two aircrafts having been landed in a normal separation. This means that a complete clearing of the runway 10 could take place in less than three minutes without impeding the running air traffic. The first route 34 of the first snow-clearing vehicle (not shown; description see FIG. 7 b) runs with an additional route parallel in longitudinal direction to the runway 10. The second route 36 of a second snow-clearing vehicle (not shown; description 7 b) runs with an additional route parallel in longitudinal direction to the runway 10. The third route 38 of a third snow-clearing vehicle (not shown; description see FIG. 7 b) runs with an additional route parallel in longitudinal direction to runway 10 so that three snow-clearing vehicles are able to move synchronically on parallel lanes.

The schematic representation of FIG. 8 describes the routes of four snow-removal groups in total, whereas groups 1 and 2 are clearing and treating one half of the runway 10 in two cycles and groups 3 and 4 are clearing and treating the other haft of the runway 10 in two cycles. The rhythm is dedicated by the landing and taking-off aircrafts. In case of low air traffic, between two successive aircrafts, the snow-clearing vehicles are repeatedly able to cross the runway 10 for clearing and cleaning. The more air traffic and the more snowfall and rain, the more devices and groups are able to operate on more sections of the runway 10 in order to clear it within shortest time and by impeding the air traffic on the runway as low as possible.

The schematic representation of FIG. 9 shows a clearing strategy. Snow-clearing vehicles do not clear or treat the runway 10 in a right angle to the longitudinal direction of the runway. However, in case of sufficient working width or low snow masses, low rain etc. the snow-clearing vehicles can cover a longer distance during crossing runway 10. In so doing, the crossing of the runway 10 is done in an acute angle to the longitudinal direction of the runway 10. Thereby, taxiways are marked with reference number 40.

The representation of FIG. 10 shows a further alternative variant of the snow-clearing procedure. In case of low snow fall, a single snow-clearing vehicle or a single snow-removal group may be sufficient to clear or treat a runway 10 completely during air traffic by crossing the runway a defined number of times. Afterwards, the snow-clearing vehicle can return to the beginning of the runway. Provided that a complete clearing of the runway is required every 60 minutes as a result of low snowfall, the average utilisation of the snow-clearing vehicles will be steered by means of a specific variation of the number of vehicles and the working width of the snow-clearing vehicles. Thus, the runway can once be cleared or treated completely within 60 minutes corresponding to the number of vehicles in time to the air traffic. In case of increased precipitation, gradually more and more vehicles or snow-removal groups will be able to “merge”. Consequently, the runway can be cleared or treated continuously and with a higher frequency without impeding the air traffic.

The single figures show the routes of single or several snow removal vehicles or snow removal groups being employed at the same time. The characteristic feature is that the runway is not cleared or treated parallel to the runway direction but it is cleared and treated in a deviating angle.

The FIGS. 11 to 17 show different graphic representations of clearing strategies and comparisons of an actual state (conventional clearing procedure) to measured timing when executing the inventive procedure (so called transverse procedure).

Further aspects of the inventive procedure may lay in the fact that machine noises, movements of devices or special noises and measures favouring the deterrence (optically), all installed on the devices, are used to keep away animals of any kind from taking-off and landing aircrafts. Thus, the risk of bird strike will be minimized for aircrafts, their engines and measuring instruments.

The operating personnel of the snow-clearing vehicles is able to identify and report possible causes of risk as a result of the permanent, narrow distanced crossings, parallel during hie clearing activity and during the whole stay on the runway.

Advantages resulting from the inventive, newly described procedure are stated as follows.

No unnecessary purchase, transport or consumption of fuel as a result of holdings, diversions, return flights etc. as a stable approach planning like in summer can be guaranteed. Similar to CAT IIIB-criteria, the reliability of a runway can be guaranteed also during an onset of winter.

No unload of freight and passengers on the airport of departure as a result of payload-reductions.

Reduction of expansive holdings and consequent operating hours (A340 costs approx. 10,000,—EUR/hour, B747—costs approx. 15,000,—

/h).

Keeping to schedules, approaching sequences, arrival and departure times etc.

Maximising the runway availability for the air traffic also in case of heavy snowfall,

Minimising of the risk of accidents due to optimisation of runway conditions and minimisation of contamination.

Avoiding diversions due to onset of winter.

Avoiding unplanned passenger stays on stopover airports at the expense of the airlines or at the expense of the passengers.

Avoiding luggage and t-eight irregularities.

Avoiding luggage forwarding and claims for compensation.

Avoiding bottlenecks regarding fuel supply on alternates not equipped for several super jumbo jets.

Avoiding bottlenecks regarding de-icing on alternates not equipped for super jumbo jets.

Avoiding slot-delays of starting aircrafts due to bottlenecks regarding loading capacity.

Avoiding double de-icing of aircrafts due to expired hold-over times caused as a result of bottlenecks regarding taking-off capacities.

Avoiding exceeding working hours and prolonging working hours of crew.

Avoiding diversions and consequential costs like handling, technique, flight security, 20 flight planning, replacement crews, transfer charges to hotel and accommodation for crew and passengers, replacement flights etc.

Avoiding increase of delays e.g. LVO (low visibly operation) and snow removal.

Avoidance of accumulations of snowy masses etc. and walking along decision difficulties, when runway must be closed for safety reasons to clean it.

Avoidance from only partially cleared areas, and solve of the conflict, that with slippery roads in winter less Runwaylength and cleared Runwaywidth are available, but width and length are needed exactly in this situation in winter.

No bigger security discounts by worse Grip of the airplane tyres in winter than in summer (of the Grip of the comparable normal tyres with a specific elastic mixture is made worse only in winter on account of the temperatures. A change of the airplane tyres for the winter with another elastic mixture does not take place). An other deterioration of the situation in winter through only partial cleared runways can be avoided.

No landing delays if the wind turns, and the landdirection must be changed which shows limiting factor, when the Snow Removal is moving in counterdirection.

Minimisation of the Runway Occupation time by worse delay coefficient and long Rollouts of the landing airplanes.

No unnecessary Go-Arounds of subsequent airplanes.

It is no unnecessary risk readiness under stress of all people involved, whether the pilot who copies the landing and target behaviour of a preceding and on snowy Runway landing pilot, or the responsible in the Tower who supports his land release on oral radio messages of the pilots with a personal feeling about the brake behaviour.

No more releases for rolling and starting on snowy ways and roads inevitably. Airplanes with more than 200,000 litres of kerosene aboard should not be led on ice and on snow. The taxi- and runways could remain cleared and cleaned also during current and usual aircraft movements

Minimisation of the accident danger by steadily sure Grip and minimisation of rescue costs.

No additional charges and stress situations of crews at the end of duty hours by contaminated land roads and walking along decision-making in fractions of seconds.

Maintenance and indemnification of the function, of perhaps available Runway-Groofings.

Avoidance of engine damages by overheating as a result of required reversal push down to the standstill of the airplane.

Rise of the reliability and security of the air traffic also during strong snowfall.

Avoidance of Foreign Object Damage (FOD), damages by foreign objects to the airplanes.

In the following, some aspects of the present invention are summarised again and stressed. The invention concerns in the essentials a procedure for cleaning or treating of Runways with the following steps:

Step 1:

At the Runway a cleaning unit is ready for crossing a active Runway, similar to waiting airplanes on the ground for crossing the active runway, e.g., behind a perhaps prescribed or defined security line.

Step 2:

After an airplane has landed, took off or went around and has passed the cleaning unit, the cleaning unit crosses the perhaps, prescribed (perhaps only virtual) security line and the Runway. Over the runway, the cleaning unit, uses tools as for example snowplow, icescratch, icecrusher, broom, brush and or de- and/or antiicing fluids, binding agent or similar, and cleans the Runway. Crossing the Runway takes place with the special sign or mark, that the real movement or treating the Runway take place, not in parallel with the runway direction, but in an deviant angle of it

Step 3:

After the duty of the cleaning unit over the Runway, the cleaning unit moves, with dug up tools, away from the Runway behind a perhaps prescribed defined security line, mainly behind the opposite side of the runway (e.g., on the right). According to working width and number of the cleaning teams, the whole Runway could be cleaned now.

A variation of the procedure encloses the following signs:

For the case, that the Runway were cleaned only partially, by too low working widths or not enough or too small cleaning units the following step follows:

Step 4:

The cleaning unit or the team of vehicles brings itself in position once more, behind the perhaps necessary security line, for another crossing of the Runway. This can mean only one turn manoeuvre or a turn manoeuvre in combination with a distance pawning according to the length of the treated runway segment. Depending on, in which angle the units removed itself from the runway and approaches it.

In the following, the steps 1 to 4 are repeated so long, until the desired runwayarea have been treated completely one time and/or the desired cleaning degree on the desired runwayarea was reached. This can lead, e.g., with constant snowfalls to an endless loop or permanent repetition of the above steps.

An other variation of the procedure plans, that according to

contamination, accumulation of contamination per time unit, desired runwayarea to be cleaned, cleaning intervals per time unit for the desired runwayarea to be cleaned, desired cleaning degree, availability of cleaning machine or staff the application of tools and means (like de- or antiicing fluids, assets gates or binding agent), the working width of a cleaning unit, the number of vehicles of one Cleaning unit, the working width of a cleaning vehicle, the speed of treatment of the machines over the Runway, according to surface state (e.g., presence of across groovings to be cleaned, presence of rigid snowy tracks to be removed or ice tracks) can be varied. (e.g., quick crossing of the Runway with loose snow, slow crossing of the Runway with rigid snow) the number of cleaning units can be varied.

With an other variation of the procedure, it can be intended, that basically in the step 1 or 4, vehicles, brought in position, or units wait for a order or a release (or arrangement) for crossing of the Runway, so that uncontrolled collisions will be avoided, security distances mainly to the air traffic are kept and impediments of the air traffic are prevented.

Besides, it can be intended with an other variation of the invention-appropriate procedure, that the vehicles, participants of the cleaning units or the leading vehicle of the cleaning unit receive orders for moving, similar to airplanes directly or indirectly or/and obey or obeys.

Besides, a preferential variation of the procedure can intend in parallel, that the working noises, the movements of the working machines or special deterrence noises or deterrence actions, e.g., on optical way which are installed on the machines, for the fact that animals of every kind keep away from starting or landing airplanes.

Furthermore the cleaners can identify and announce danger springs for airplanes parallel during the cleaning activity or during the whole stay on or at the runway or announce this dangerfakts in a contemporary way.

An other variation of the procedure intends, that not the air traffic has priority compared with the cleaning vehicles or cleaning units, but the cleaning vehicles and cleaning units compared with aircraft.

In addition, a procedure can intend that the angle for crossing of the runway is adapted by the cleaning vehicles or cleaning units, to the relative angle of perhaps available Runway-Groofings (grooves) to the Runway and a thorough cleaning is also allowed for across grooves (Across to the land direction or start direction of airplanes).

It is possible, that one or several leadership vehicle(s), can be followed by one or several working widths, or bring them along, and that the pawning with of a turn, conditional by the respective working width or sum of the working widths by several vehicles, which are led by a leadership vehicle with it whole (sum of) working width(s) after the turn manoeuvre for the defined or treated segment of the Runway takes place, and/or also the whole desired route, takes place in a precise manner, or is automatically followed, which precision is known in farming known as Precision Farming or automatic steering system (e.g. by means of GPS) or similar to it, what means, that with technology for automatic steering from vehicles on agricultural fields, the present application case and described procedure is able to operate, also during thickest snowfall, fog, darkness and such on, and can be carried out certainly and reliably. Also increase or decrease of working units (numbers) or segments of the working widths can take place according to the demand also without disturbance and with the desired effect.

The whole route which is necessary to treat the runway completely one time or several times (overlappings are also exactly determinable), can be driven by means of automatic steering system. 

1. Method for cleaning, clearing and/or treating an elongate path, especially a straight solid way, especially a runway and/or a takeoff and/or a landing strip of a airport, which is frequently used by aircrafts taking off or landing in a longitudinal direction, in irregular time patterns, whereby cleaning or clearing movements for at least one length segment of the runway are carried out with defined working width, in a sloping or vertical angle to the longitudinal direction of the runway and in cycles of two or more similar, successively following cleaning- or clearing trips and/or movements of at least one clearing tool/vehicle.
 2. Method of claim 1, whereby the cleaning or clearing movements are prosecuted by several cleaning or clearing movements, in each case parallel and in possibly around the working width at the side to the longitudinal direction of the runway transferred.
 3. Method of claim 2, where a cleaning- and/or clearing movement is followed by a back movement in an opposite direction (counterdirection) without cleaning or clearing, and after that a side transferred cleaning and/or clearing movement in the same (identical) direction to the preceding cleaning and/or clearing movement follows.
 4. Method of claim 2, where a cleaning- and/or clearing movement in one direction is followed by a side transferred cleaning and/or clearing movement in counterdirection and again another side transferred cleaning and or clearing movement in the same (identical) direction to the prepast clearing movement follows.
 5. Method of claim 4, where two or more cleaning and or clearing movements are carried out at the same time and/or time-transferred at different places (segments) along the longitudinal direction of the runway.
 6. Method of claim 1, whereby the runway is cleaned or cleared by means of at least one cleaning and/or clearing vehicle and/or machine, in particular by means of two, three or more cleaning and/or clearing vehicles and/or above the runway moved cleaning and or clearing devices, which operate over the runway at the same time and/or time transferred.
 7. Method of claim 6, where at least one cleaning and or clearing vehicle and or machine is positioned on the edge of the runway or in distance to the runway, while the runway is used by airplanes in longitudinal direction.
 8. Method of claim 6, where the runway or segments of the runway are cleaned until the runway is used in longitudinal direction (by aircraft), and the runway is cleaned again immediately (directly) after a use in longitudinal direction, e.g. in sloping (slanting) or vertical angle to the longitudinal direction of the runway.
 9. Method of claim 8, where at least one already passed segment of the runway, will be cleaned and/or cleared by one or several cleaning and/or clearing vehicles and/or devices, while other segments of the runway in longitudinal direction are still used by an airplane.
 10. Method of claim 1, whereby the cleaning and/or clearing vehicles are steered in defined way, by means of optical systems and/or by means of satellite-supported trace steering systems. 